The organ strains of Procol Harum’s “A Whiter Shade of Pale” sounded through Court 56 of Britain’s High Court as the band’s former organ player, Matthew Fisher, sued an ex-bandmate for a share of copyright in the multimillion-selling song.

Fisher’s lawyer, Iain Purvis, said the song “defined what is sometimes called the summer of love in 1967,” and had achieved cult status.

He said Fisher had composed the organ melody, and particularly the eight-bar Hammond organ solo, which gives the song its distinctive baroque flavor.

Purvis said the solo “is a brilliant piece of work and it is crucial to the success of the song.”

“Our case, in essence, is that Mr. Fisher wrote the entirety of the organ tune,” he said.

Fisher is suing Procol Harum singer Gary Brooker and publisher Onward Music Ltd. for a co-author credit and a share of the song’s copyright and royalties.

Brooker, who is credited as the song’s author with lyricist Keith Reid, says the pair wrote the song before Fisher joined the band in March 1967.

Brooker has said the melody was inspired by Johann Sebastian Bach’s “Air on the G String” and “Sleepers Awake.”

Defense lawyers said the fact Fisher had waited almost four decades to bring his claim was “bizarre and obviously prejudicial.”

“Mr. Fisher’s claim should fail on that ground alone,” they said in court papers.

The song, renowned for its mystifying lyrics — beginning “We skipped the light fandango, turned cartwheels cross the floor” — topped the British singles chart for five weeks and was a top 10 hit in the United States. Rolling Stone magazine has ranked it 57th in a list of the 500 greatest songs of all time.

Purvis said a Web site compiled by a fan lists 771 recorded cover versions, “most of them, sad to say, disastrous.”

Fisher, now a computer programmer, left the band in 1969. Brooker, 61, still tours with Procol Harum. The two sat facing Judge William Blackburne and did not look at one another on the first day of the five-day hearing.

Blackburne later asked Fisher to play the organ melody on an electric keyboard near the witness box.

Blackburne, who studied both music and law at Cambridge University, requested access to the keyboard and sheet music of “A Whiter Shade of Pale” so he could run through the song after court hours.

Judges are not always familiar with popular music, and Purvis noted that “one always risks in these cases a ’what-are-The-Beatles’ moment” — a reference to a famous but possibly apocryphal story of a judge who purportedly asked that question during a case in the 1960s.